Article ID: JJID.2016.078
Although first mumps vaccine was licensed many years ago, mumps vaccine added to Iran's Expanded Program on Immunization in 2003. Therefore, majority of Iranian young adults born before 2003 are unvaccinated and their immunity resulted of natural infection. For evaluation of cellular responses against mumps virus following natural infection, we investigated ninety Iranian unvaccinated young adults aged 20-30 years. Mumps specific memory CD4+ and CD8+ proliferation and frequency of cytotoxic lymphocyte CD8+ CD107a were evaluated using sensitive technique of flowcytometery. Our results showed thirty three of volunteers were seronegative, but twenty eight of them showed degranulation of CD8+ T lymphocyte and expression of CD 107a and proliferation of CD4 and CD8 T cells in response to mumps antigen stimulation. In all seroposetive subjects degranulation of CTLs and proliferation of CD4+ and CD8+ T lymphocytes were detected. Proliferation of T cells and degranulation of CD8 T cells in seroposetive subject were higher than seronegative subjects. We concluded however natural mumps infection and subclinical reinfection could induce a good protection but serve complications of mumps infections introduce the need of mumps vaccination. Natural boosters due to wild-type virus may help to maintenance of immunity in populations with high coverage of vaccination.
